Will your whole spell fail if a person walks through your Circe especially out of spite? I would guess yes in most cases, but in the spell I was casting the circle was optional and only used as a boost

Normally I would say yes, but in your case since the spell was optional it may still work but not in the initial way you wanted it, but because a person walked into it and it wasnt an animal then any energy you raised was probably stripped down.

Next time i suggest that you do it in a more private space! Only animals should be allowed in it. Hope this helped!!!!!

i would say it would weaken it but not undo it. a circle creates holy ground and protection against negativity. if the circle is broken, it weakens the energy is the area you are casting, but if you ignore it and continue the spell, it should still work, it just wouldn't be as strong.

if you stop, close the circle, and continue casting, i would say your spell would fail because you broke your concentration. i would start from the beginning if you chose to recast the circle.

if someone out of spite is deliberately breaking the circle, then go some place you can lock a door to keep them out. the one nice thing about circle than say a church, is if someones bothering you, you can move your holy ground wherever. much harder to move a building.

That is rather rude of that person to do that out of spite, but I do not think that you need to cast a circle if you are doing a spell. I do have to agree with you though. The reason is that the person is disturbs your concentration which leaves you loose your focus.

This is the reason why I lock the doors, but if your family are like mine then I know how it feels. It is the reason why I try to modify things.

I think that is the reason why I use candle magick and lots and lots of incense. It bugs my siblings that they will not enter the room if they see incense. So that is my tip to ward off siblings (lol).